gRPC reference documentation

docs/modules/ROOT/nav.adoc

@@ -38,6 +38,7 @@
 ** xref:reference/commons-pool.adoc[Apache Commons Pool]
 ** xref:reference/jvm.adoc[JVM]
 ** xref:reference/cache.adoc[Cache]
+** xref:reference/grpc.adoc[gRPC]
 ** xref:reference/okhttpclient.adoc[OkHttpClient]
 ** xref:reference/jetty.adoc[Jetty and Jersey]
 ** xref:reference/netty.adoc[Netty]

docs/modules/ROOT/pages/reference/grpc.adoc

@@ -0,0 +1,35 @@
+[[overview]]
+= gRPC Instrumentation
+
+https://grpc.io/[gRPC] is a modern open source high performance Remote Procedure Call (RPC) framework that can run in any environment.
+
+Below you can find an example of how to instrument gRPC with Micrometer.
+
+First, client and server side interceptors need to be setup.
+
+[source,java,subs=+attributes]
+-----
+// Setting up interceptors
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java[tags=setup, indent=0]
+
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java[tags=setup_2, indent=0]
+-----
+
+Next, server and channels need to have the interceptors added.
+
+[source,java,subs=+attributes]
+-----
+// Adding them to the server and client side
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java[tags=example, indent=0]
+-----
+
+Below you have an example of usage with the result assertions.
+
+[source,java,subs=+attributes]
+-----
+// Usage example
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java[tags=result, indent=0]
+
+// Observation outcome
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java[tags=assertion, indent=0]
+-----

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/grpc/GrpcObservationTest.java

@@ -79,10 +79,13 @@ class GrpcObservationTest {
 
     ContextAndEventHoldingObservationHandler<GrpcClientObservationContext> clientHandler;
 
+    // tag::setup[]
     ObservationGrpcServerInterceptor serverInterceptor;
 
     ObservationGrpcClientInterceptor clientInterceptor;
 
+    // end::setup[]
+
     TestObservationRegistry observationRegistry = TestObservationRegistry.create();
 
     @BeforeEach
@@ -97,8 +100,10 @@ void setUp() {
             .observationHandler(serverHandler)
             .observationHandler(clientHandler);
 
+        // tag::setup_2[]
         this.serverInterceptor = new ObservationGrpcServerInterceptor(observationRegistry);
         this.clientInterceptor = new ObservationGrpcClientInterceptor(observationRegistry);
+        // end::setup_2[]
     }
 
     @AfterEach
@@ -116,6 +121,7 @@ class WithEchoService {
 
         @BeforeEach
         void setUpEchoService() throws Exception {
+            // tag::example[]
             EchoService echoService = new EchoService();
             server = InProcessServerBuilder.forName("sample")
                 .addService(echoService)
@@ -124,15 +130,18 @@ void setUpEchoService() throws Exception {
             server.start();
 
             channel = InProcessChannelBuilder.forName("sample").intercept(clientInterceptor).build();
+            // end::example[]
         }
 
         @Test
         void unaryRpc() {
+            // tag::result[]
             SimpleServiceBlockingStub stub = SimpleServiceGrpc.newBlockingStub(channel);
 
             SimpleRequest request = SimpleRequest.newBuilder().setRequestMessage("Hello").build();
             SimpleResponse response = stub.unaryRpc(request);
             assertThat(response.getResponseMessage()).isEqualTo("Hello");
+            // end::result[]
 
             verifyServerContext("grpc.testing.SimpleService", "UnaryRpc", "grpc.testing.SimpleService/UnaryRpc",
                     MethodType.UNARY);
@@ -144,6 +153,11 @@ void unaryRpc() {
                     GrpcServerEvents.MESSAGE_SENT);
             assertThat(clientHandler.getEvents()).containsExactly(GrpcClientEvents.MESSAGE_SENT,
                     GrpcClientEvents.MESSAGE_RECEIVED);
+            // tag::assertion[]
+            TestObservationRegistryAssert.assertThat(observationRegistry)
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.client"))
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.server"));
+            // end::assertion[]
         }
 
         @Test
@@ -174,6 +188,9 @@ public void onFailure(Throwable t) {
 
             await().until(() -> futures.stream().allMatch(Future::isDone));
             assertThat(responses).hasSize(count).containsExactlyInAnyOrderElementsOf(messages);
+            TestObservationRegistryAssert.assertThat(observationRegistry)
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.client"))
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.server"));
         }
 
         @Test
@@ -213,6 +230,9 @@ void clientStreamingRpc() {
             verifyServerContext("grpc.testing.SimpleService", "ClientStreamingRpc",
                     "grpc.testing.SimpleService/ClientStreamingRpc", MethodType.CLIENT_STREAMING);
             assertThat(serverHandler.getContext().getStatusCode()).isEqualTo(Code.OK);
+            TestObservationRegistryAssert.assertThat(observationRegistry)
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.client"))
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.server"));
         }
 
         @Test
@@ -244,6 +264,9 @@ void serverStreamingRpc() {
             assertThat(clientHandler.getContext().getStatusCode()).isEqualTo(Code.OK);
             assertThat(clientHandler.getEvents()).containsExactly(GrpcClientEvents.MESSAGE_SENT,
                     GrpcClientEvents.MESSAGE_RECEIVED, GrpcClientEvents.MESSAGE_RECEIVED);
+            TestObservationRegistryAssert.assertThat(observationRegistry)
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.client"))
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.server"));
         }
 
         @Test
@@ -293,6 +316,9 @@ void bidiStreamingRpc() {
 
             assertThat(serverHandler.getContext().getStatusCode()).isEqualTo(Code.OK);
             assertThat(clientHandler.getContext().getStatusCode()).isEqualTo(Code.OK);
+            TestObservationRegistryAssert.assertThat(observationRegistry)
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.client"))
+                .hasAnObservation(observationContextAssert -> observationContextAssert.hasNameEqualTo("grpc.server"));
         }
 
         private StreamObserver<SimpleResponse> createResponseObserver(List<String> messages, AtomicBoolean completed) {